Honduran authorities have evidence implicating high-level business executives and state agents in the murder of prominent human rights activist Berta Caceres, but have yet to arrest them, a damning new report by a team of international lawyers says.

The report, released on Tuesday morning, also says there have been serious flaws in the government’s investigation into the March 2016 murder of Caceres and, despite orders from a judge, officials have not turned over the remaining evidence to the independent team.

Caceres, one of the most well-known activists in Latin America and a winner of the prestigious Goldman Environmental Prize, was gunned down in her home just before midnight on March 2, 2016, after years of threats related to her work protecting indigenous communities and campaigning against a hydroelectric dam project.

The independent team behind Tuesday’s report is comprised of five lawyers from Colombia, Guatemala and the United States and was organised at the request of Caceres’ family last year due to concerns over the official investigation.

The family, along with human rights activists and UN officials, repeatedly called on the Honduran government last year to allow for an independent inquiry but the government refused.

To date, eight men have been arrested in connection with the murder, including an active-duty member of the Honduran military and two employees of the company behind the dam project, Desarrollos Energeticos (DESA).

DESA had not responded to e-mails seeking comment from Al Jazeera at the time of publication, but has, in the past, denied any involvement in the murder of Caceres.

When the Al Jazeera’s Fault Lines interviewed a spokesman for the Attorney General’s office last year during an investigation of the murder of Caceres, he acknowledged that the men arrested were not the ones who planned the assassination or gave the ultimate order to carry it out.

Despite this, the Honduran government has yet to arrest anyone else in the 20 months since Caceres was killed.

Long-calculated plan

The independent group’s report says that evidence points to not only a large network that extends to executives in DESA, as well as state officials, but to a long-calculated plan shrouded in corruption.

The report says that the group “has been able to establish the participation of executives, managers and employees of DESA, of private security personnel hired by the company, of state agents and parallel structures to state security forces in crimes committed before, during and after March 2, 2016, the day of the assassination”.

Roxanna Althoz, a US lawyer who was part of the independent group, told Al Jazeera that one of the most troubling revelations from the group’s investigation is that the government has the same data the lawyers based their conclusions on, in addition to even more evidence.

Althoz said that the public ministry “had information about the about the identity and actions and conduct of the intellectual authors for a year and a half and has failed to act”.

FAULT LINES – Honduras: Blood and the Water

A spokesman for Honduras’ attorney general’s office had not responded to requests for comment from Al Jazeera at the time of publication.

The lawyers made several visits to Honduras to conduct dozens of interviews and had access to nearly 40,000 pages of evidence from the government’s own investigation, including text messages, WhatsApp messages and group chats and other telephone and cellular data.

WhatsApp messages

The report includes a number of WhatsApp messages from Sergio Rodriguez, one of the eight men arrested and who was a social and environmental manager for DESA.

Among the messages from Rodriguez were those from the day after the murder, including one where he forwards a copy of the police report of the crime scene that he received just hours after the killing to an undisclosed DESA executive.

At this time, the report says, Caceres’s family had not yet received that information from police.

The executive later replies, telling him to “relax” and that “everything will turn out fine, you’ll see. Don’t panic and pass it on to others.”

WhatsApp messages documented in the report also show frequent surveillance of Caceres and colleagues from the indigenous rights groups she led, COPINH, something they repeatedly made known to Caceres, according to her daughter.

“They would send her pictures of a place she had been to saying ‘I saw you here,'” Laura Zuniga Caceres told Fault Lines last year.

“That was their control mechanism, their way of saying ‘we are watching you,'” Victor Fernandez, Berta Caceres’s lawyer, told Fault Lines at the time.

‘No one is safe’

Honduras continues to have one of the world’s highest rates of murders against land rights and environmental activists, particularly since a military coup in 2009.

Many of the projects tied to the murder of land rights activists in Honduras, including the Agua Zarca dam project, involve some of the country’s wealthiest and most powerful families.

Despite millions of dollars in aid from the United States and support for investigative agencies, including the unit responsible for investigating the murder of Caceres, entrenched impunity has long stifled any meaningful investigations in Honduras.

Caceres received numerous death threats in the years leading up to her murder.

But in the initial days after the killing, officials first focused their investigation on members of COPINH, as well as a former boyfriend.

Fellow activists made and placed a mosaic in the halls of COPINH, the Civic Council of Popular and Indigenous Organizations of Honduras [Kavitha Chekuru/Al Jazeera]

In one of the WhatsApp messages listed in the report, a public relations executive with DESA tells Sergio Rodriguez to raise the question of why “COPINH wants to maintain its role as a victim”.

The PR official, according to the report, goes on to suggest that Rodriguez should, “in passing continue to press the possible motive of passion in the murder of Ms. Berta Caceres”.

Gustavo Castro, the only witness to the murder, told Al Jazeera’s Fault Lines last year that when he met with authorities after the murder, they didn’t seem to be interested in what he had to tell them.

“When they requested that I do a police sketch, the sketch artist was drawing a member of COPINH,” Castro recounted. “I said, ‘That’s not what he looks like! He looks different!’ He erased it and then he drew it again.”

The independent group’s report is based only a fraction of evidence available and even then, the team of lawyers says they were able to point to larger levels of responsibility for Caceres’ murder and new lines of investigation – something the Honduran government has yet to do.

While the lawyers were able to say others were involved, they did not superficially name anyone besides the eight that have been arrested because authorities have not charged anyone else

But the group is still awaiting the larger remaining portion of evidence in the possession of the Honduran government.

“We are very concerned about what’s going to happen with that evidence,” she added. “What we found is an investigation that falls well short of international standards and seems to be driving towards impunity.”

Given Berta Caceres’ international profile, the fact that the intellectual authors of her murder have not been arrested so long after the crime seems to be proof of the deep roots and staying power of Honduras’ impunity.

When Al Jazeera visited Honduras last year, Caceres’ daughter, Laura, surrounded by photos of her mother, stated the most glaring truth that has emerged since her mother was killed: “After my mom’s assassination, they showed that nobody is safe here.”